﻿using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;

namespace BraveryLand;

public class GlobalSpacebarListener : IDisposable
{
    private const int WH_KEYBOARD_LL = 13;
    private const int WM_KEYDOWN = 0x0100;

    private LowLevelKeyboardProc _proc;
    private IntPtr _hookID = IntPtr.Zero;

    public event EventHandler SpacebarPressed;

    public GlobalSpacebarListener()
    {
        _proc = HookCallback;
        _hookID = SetHook(_proc);
    }

    private IntPtr SetHook(LowLevelKeyboardProc proc)
    {
        using (Process curProcess = Process.GetCurrentProcess())
        using (ProcessModule curModule = curProcess.MainModule)
        {
            return SetWindowsHookEx(WH_KEYBOARD_LL, proc, GetModuleHandle(curModule.ModuleName), 0);
        }
    }

    private delegate IntPtr LowLevelKeyboardProc(int nCode, IntPtr wParam, IntPtr lParam);

    private IntPtr HookCallback(int nCode, IntPtr wParam, IntPtr lParam)
    {
        if (nCode >= 0 && wParam == (IntPtr)WM_KEYDOWN)
        {
            int vkCode = Marshal.ReadInt32(lParam);

            if ((Keys)vkCode == Keys.Space)
            {
                OnSpacebarPressed(EventArgs.Empty);
            }
        }

        return CallNextHookEx(_hookID, nCode, wParam, lParam);
    }

    protected virtual void OnSpacebarPressed(EventArgs e)
    {
        SpacebarPressed?.Invoke(this, e);
    }

    public void Dispose()
    {
        UnhookWindowsHookEx(_hookID);
    }

    ~GlobalSpacebarListener()
    {
        Dispose();
    }

    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern IntPtr SetWindowsHookEx(int idHook, LowLevelKeyboardProc lpfn, IntPtr hMod, uint dwThreadId);

    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool UnhookWindowsHookEx(IntPtr hhk);

    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode, IntPtr wParam, IntPtr lParam);

    [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern IntPtr GetModuleHandle(string lpModuleName);
}